The most common closure is a zipper, but some rainbow pencil cases use clasp closures or snap-tight lids on hard plastic boxes.
Capacities in listings range roughly from about 50 pens or pencils up to around 60, depending on design and internal organization.
Dimensions vary by model. Examples listed include 1.13 in (H) x 4.25 in (W) x 9.0 in (D); 2.3 in (H) x 8.2 in (W); 2.5 in (H) x 5 in (W) x 8.5 in (D); and 3.16 in (H) x 8.71 in (W) x 2.8 in (D).
Common organization features include front pockets, zippered mesh compartments, elastic pen slots or bands, multiple internal pockets and bands, and expansion zippers on some fabric cases.
Many options are described as compact enough to fit in backpacks or drawers; some designs are stackable for space-saving. One silicone pouch lists a weight of 0.5 pounds, indicating lightweight portability for some models.
Some zippered EVA cases mention a lifetime warranty (registration required), and at least one pouch offers a satisfaction guarantee with a money-back promise.
